1. Field of the Invention
The present invention relates to solid-state storage devices. More specifically, the present invention relates to electrically erasing and/or physically damaging solid-state storage devices.
2. Description of the Related Art
Solid-state storage solutions are used to store a wide variety of data including sensitive information not intended for unauthorized users. For example, a host computer system may store a person's personal or financial information on a solid-state memory device such as an advanced technology attachment (ATA) flash disk or a removable flash memory card. A subsequent user's unauthorized access to the solid-state memory device could result in identity theft wherein the subsequent user misappropriates and misuses the personal and financial information. Solid-state storage solutions also store sensitive information including, for example, trade secrets, security information, military information, credit card information, or other information that a user desires to keep confidential.
One approach to reducing unauthorized access to data stored on a solid-state memory device is to electrically erase a memory array within the memory device. Conventional systems use industry standard command sets such as those provided by ATA, CompactFlash (CF) card or PC card (also know as a PCMCIA card) standards to erase memory arrays. Generally, a host sends standard read, erase and write commands to the memory device several times to ensure that the memory array is erased. Some systems also send additional commands to write a data pattern to the memory array to meet industry standard data sanitation specifications.
Such erase and sanitation procedures are cumbersome and generally require the host to repeatedly handshake with the memory device. Further, the host system will generally erase and sanitize multiple memory chips in a memory device sequentially with handshaking operations between erase operations. Thus, it can take several minutes or hours to complete an erase and sanitation procedure. In some applications such as avionics or power sensitive systems, sufficient time and/or power may not be available to adequately erase and sanitize the memory device. For example, it may not be possible to erase and sanitize the memory array during intermittent system power failures.
Solid-state memory arrays typically comprise a semiconductor material such as silicon or the like. Even when the memory array is erased, it may still be possible to retrieve data by examining the semiconductor material for the effects of hysteresis. In military or other security sensitive applications, such data retrieval is generally unacceptable. Thus, the memory array is typically physically destroyed using, for example, one or more instruments to gain access to and destroy the memory array. However, there is not always enough time to physically locate and destroy the memory array. For example, a pilot forced to land a military aircraft in enemy territory may have very little time to electrically erase or physically destroy sensitive information in the memory array.